In recent years mowers and weed trimmers of the whirling cutter type, in which the cutter consists of a strong flexible cord held taut by its centrifugal force, have become popular because they essentially eliminate the hazard of serious injury from contact with a whirling rigid blade with a sharp edge.
Such mowers are typically provided with a reel of cord from which the free end is drawn to a prescribed distance from the axis, and the cord is then clamped. After the free end is worn away by use, the machine is stopped so that the cord can be unclamped, drawn out again to the prescribed length, and reclamped.